The Graff Purplish-Red Diamond

Red diamonds are among the rarest in the world, and the most notable red diamonds in existence are relatively small when compared to other famous fancy colored diamonds. The largest known red diamond, the triangle-shaped Moussaieff Red, weighs in at 5.11 carats, whereas some of the world's notable white, yellow, blue, and pink diamonds weigh hundreds of carats.

Fourth in size among red diamonds after the Moussaieff Red, a 5.11-carat triangular brilliant; the 5.05-carat emerald cut Red Diamond; and the 5.03-carat De Young Red round brilliant, is the 2.26-carat purplish-red diamond owned by London jeweler Lawrence Graff. The three red diamonds next in size to the Graff Purplish-Red - the Unnamed Red, the Hancock Red, and The Lady in Red - all weight less than two carats, with The Lady in Red barely exceeding half a carat.

Graff paid the highest auction price in history for a red diamond when he bought the stone in 2007 for over $2.66 million. The sale beat the previous record price paid for a Red Diamond by more than $1 million.

When the hammer finally came down (Graff had been bidding anonymously), the diamond turned out to have garnered not only the highest auction price ever paid for a red diamond, but also set a record for the highest red diamond per-carat price - just over $1.18 million. This beat the 20-year record set by the 1987 sale of the Hancock Red Diamond, which the Sultan of Brunei bought for $880,000.

The precise color and clarity grades of the Graff Purplish-Red diamond are not known, but its color is deemed highly unusual, as is its octagonal shape. Nor is the source of this particular red diamond known. It would seem likely that the Graff Purplish-Red diamond was mined at the Argyle Mine in Western Australia, which produces 90% of the world's rare pink and red diamonds, but its size is inconsistent with the average size of the red diamonds mined there.

When the diamond was sold in 2007, it was not auctioned as a loose stone but rather set in a ring. The purplish-red diamond formed the center of a flower, with white diamonds set around it as petals.

A red diamond showing up at auction is a rare event indeed - fewer than 20 diamonds worldwide are recognized as bearing an official grade of "red." Red diamonds comprise approximately 1/60 of all pink diamonds, which makes the chance of unearthing a red diamond a scant one in 60,000,000.